German Patent Application No. DE 197 12 921 A1 describes a fuel-injection system which includes a cylinder head and at least one fuel injector having piezoelectric actuation. A fuel-supply line through which fuel flows into the individual fuel injector under relatively low pressure (3 to 4 bar) on the side, below the actuator, is provided in the cylinder head. Because of the actuator lifts and the action of a piston pump integrated in the fuel injector in the discharge-side region, the fuel is injected into the combustion chamber under a much higher pressure.
In particular when using this system in internal combustion engines having fuel injectors of a simpler construction and high-pressure injection without integrated pump, a disadvantage is that the fuel lines located outside the cylinder head will have been produced in a very complex manner and may be costly due to their unavoidable flexibility. The required space, the installation effort and the susceptibility to faults, especially with respect to external mechanical influences, is increased considerably.